RADARSAT-1

The push to provide Canada with its own Earth-observation satellite brought together the federal and provincial governments, along with more than 100 private companies and other organizations, to build RADARSAT-1. The project cost $620 million, and NASA agreed to provide a Delta II rocket to launch the satellite in exchange for access to RADARSAT-1 data. The satellite was launched in 1995, and has been providing imagery to customers in nearly 60 countries since then.

The technology deployed on RADARSAT-1 was chosen with the unique demands of Canada’s remote north in mind. Ordinary optical cameras don’t work in the dark, so they would be useless during the long, dark winters above the Arctic Circle. A radar imager, on the other hand, can take clear images in light or dark conditions, and penetrates through clouds. RADARSAT-1 is equipped with a “synthetic aperture radar” (SAR), which uses sophisticated mathematical techniques to obtain higher resolution than a traditional radar antenna. It can resolve features as small as 8 metres from its height of 798 kilometres above the ground. The frequency of the radar signal, 5.3 GHz, was chosen because it is optimal for distinguishing between different kinds of snow and ice.